Although Expensive, MHZ has a good unit that pretty much covers all bases:
www.MHZusa.com
Look under ENGINE ACCESSORIES.
This is a lower cost unit that kills engine on low of complete power loss. It does not however monitor signal quality...units like these work well in conjunction with a radio that features signal failsafe, like some PCM and DSM radios.
69.49.183.35/ProductDetails.as...uctCode=ACC1S15